Piston-packing.



NO. 840,793. PATENTED JAN. 8, 1907.

. J. J. MOGBEE PISTON PA GKIN G.

No. 840,'793. PATENTED JAN. 8, 1907.

' J. J. MGGEE.

PISTON PAGKING.

APPLIGATION PILED JUNE 29,1906.

2 SHEETS-SHEET 2.

acco 51 I 26 l 2 l LJ JOHN J. McGEE, OF NEW YORK, N. Y.

v PISTDN-PACKING.

Specification of Letters Patent.

Patented J' an. 8, 1907.

Application filed June 29, 1906. Serial No. 328.981.

To all whom it may cancer-'nr Be it known that I, JOHN J. MGGEE, a citi- 'zen of the United States, residing at the city of N ewYork, in the `borough of 'Brooklyn and State of New York; 'have invented certain new. and: useful Improvements in Piston- Packing, of which thefollowing is a full, clear, and exact description.

My invention relates to metallic packing for pistons, and particularly the pistons of steam-engnes.

- The principal object of the invention is to provide a packing which'is perfectly 'steamtight, which remains tight in spite of considerable wear, and which imposes only very slight resistance to the free movement of the iston.

A further object of the invention is to provide a strong and practical construction convenient to manufacture and easy to assemble into place.

With these and other Objects in view the invention consists in the construction, combination, in the location, and in the arrangement of parts, as hereinafter set forth and shown, and finally particularly pointed out in the appended claims.

In the drawings, Figure l isa side view, partly in section, of a piston and packing emodying the principles of my invention. Fig. 2 is a sectional view of the same on the line II II of Fig. 1 looking in the direction of the arrows. Fig. 3 is a section on the line III III of Fig. 1 also looking in the directionof the arrows. Fig. 4 is a perspective view showing the two ends of one of the packing-rings. The two ends are separated to more clearly show the construction. Fig. 5 is a perspective view showing adj acent portions of a pair of sections of the central or bull ring. Fig. 6 is a perspective view showing a portion of a spring-ring which is employed with each of the packing-rings. Fig. 7 is a view showing' a slightly-modified form of spring-ring. Fig. 8 is 'a detail view looking toward a. portion 'of the inside of one of the spring-rngs and showing a modified construction of certain eXpanding-wedges which I employ.

The pistons of steam-engines, gas-engines, compression-pumps, and like machinery are ordinarily provided with circumferential grooves, in which are contained packingrings which make, or should make, a fluidtight joint against the cylinder-wall in spite of the continuing wear of the surfaces. The problem of properly packing the piston so as to 'absolutely prevent leakage in use and at the same time to have suflicient freedom of motion has always been a diflicult one and never fully solved. The piston bears against the cylinder-wa'll throughout a considerable area' and, furthermore, travels at a considerable speed, so that the power lost by friction is multiplied to a large figure. 4 Not only is ower thus lost and coal and steam wasted, ut the increased friction produces increased Wear, soithat the piston-rings become less tight and eventually leak steam orthe fluid used. In carrying out m'y invention I aim to Overcome these defects and to provide a piston which moves with very slight resistance in the cylinder, but which is perfectly fight under all conditions. I further aim to mm'mize wear, and particularly unequal wear, on the cylinder, piston, and packingrings and to havesuch wear as occurs compensated for, so that the piston remains fluidtight for a long period.

Referring now to the drawings, in which like parts are designated by the same reference-sign, 1 indicates a piston bolted or otherwise Secured to the piston-rod 2 and which travels in any' suitable cylinder. (Not shown.) The main body of this piston isformed of a casting 3, with fiatfendfaces 4 and cylindrical side Walls 5, which, however, are divided from one another by annularribs 6, carefully machined with 'flat faces 7. S v

indicates a pair of flat metal disks bolted to the end faces 4 of the iston and forming flat Walls 9, which are similar to the opposed Walls 7 of the intermediate ribs 6. in this way there are produced three annular grooves or channels crcumferentially about the piston. The central one oi these channels is denoted by the reference-numeral 10 in the drawings, and the two side channels are indicated by reference character 11.

Within the central channel 10 is contained what I shall term the bull-ring. This is a ring in one or more sections,.preferably three sections, which serves mainly as a bearing or guide for the piston in its movement against the cylinder-walls; but this ring -also has a function of keeping the piston steam-tight should the other rings pqartially fail from any cause to accomplish t is. The sections ol' the central ring or bull-ring are designated at '12 and are' conveniently made of phosphorbronze or some material having wean'ng and antifriction qualities. The various'sections of the bull-ring are lap-jointed together, so as IOO IIC

to Secure the double function of a steam-tight joint and a joint which will guide and hold the three sections into a continuous ring. The particular joint which I use in practice is shown best in Figs. 1 and 2 and Fig. 5. Each of the sections 12 has an extension 13, which laps u on the extension of the other and is capab e of relative movement thereon.

14 indicates a rib or tongue projecting from the side face of one extension 13, and 15 indicates a corresponding groove or channel in the other extension, which receives said ton ue and keeps the two sections properly guided in their required relation. This tongue is particularly convenient in turning and finishing the bull-ring when it is manufactured and in afterward assembling it into place.

The inside surface of the bull-ring is cireumferentially recessed or channeled, as clearly shown at 16 in Fig. 1. 17 indicates a spring-ring contained in this groove or channel, so as to about fit the same. This springring 'issplit at one point 18, Fig. 2, and exerts ashg'ht force to impel the sections of the bullring outward. The resiliency of this spring is such as to Overcome the gravity of the u per sections of the bull-ring, so that these` o not sag away from the cylinder-wall under a-ny circumstances.

By these means the sections of the bul l ring are held in proper concentric or annular relation with one another,

' closely fittingrwit'hin -the central groove 10 of tie the iston. hese sections are relied upon to `gi i e the piston within the cylinder-walls and aiso to furn ish a packing in addition to the side r-ings should it 'become necessary.

The two side rings 19 and which I shall term the main packing-rings" are continuous except for one split or division. Referring to Fg. 4, I have ill-ustrated the nature of this split or division. One end of the r-ing 19 is deeply recessed, as shown at 20, leaving only a web 21. 22 indicates an extens'ion of the ring, which is at 'one side of and out of the plane thereof. 'This extension has a fiat wall 23 in the plane of one of the edges of the ring. The other end of the ring is slight l cut away, as shown at 24, to receive the we 21. The two ends may now be fitted together, 'in which -relaticn they will form a fiud-tight join When brought together in relation, the rings are returned and finished so as 'to 'be truly concentric. They are also tempered in such a way as to have little or no outward resil-iency in this relation. Ilhese main packing-rings 19 are closely contained in the ohannels 11, above described, where they ma be positioned b initially removing the en plates 8. In or er'to accommodate the extension 22, I rovide recesses 25 in the ribs 6, in which-suo extensions are received.

The main packing-rings 19 have enough resiliency to permit their expansion to accommodate wear of the cylinder-walls; but their spring tension is not such as to cause this eX- panson without se arate means. The separate means which use in practice consists of spring-rings 26, which may have a T-section, as shown in Fig. 6, or a U-shape'd section, as shownin Fig. 7. These rings have one split or division and exert an outward force upon the main packing-rings 19. The purpose of this construction is to avoid the unequal bearingpressure which would be inducedif the springpressure were in the main packing-rings direct rather than in the underlying spring-rings.

I provide additionalv means for expanding the' main packin -rings 19 outward, partieularly when there IS heavy fluid-pressure in-the cylinder, and therefore a greater need of efficient packing. I have shown a convenient construction having a plurality of wedges 27, of which three is a convenient number, and Which are guided to have a longitudinal movement within the body of the piston, so that their wedge-faces 28 bear against the under side of the spring-rings 26 and expand the latter outward. The ends of these wedges are fitted with little pistons 29, which move in the end plates 8 of the piston. 30indicates pins which project into recesses of the wedges to limit their movement. 'The operation of these wedges will be obvious. When the piston is in action and fluid-pressure is exerted against either of the lates 8, the pistons 29 are impelled inward y such pressure, and their wedge-faces 28 become efiective to cam outward the spring-rings 26 and the main packing-rings 19.

I have already referred to an alternative construction of the spring 26, and which is illustrated at 26' in Fig. 7. Other features of the invention may be likewise modified. For example, only a single wedge 27 may be used for each of the main packing-rings, and this may be dsposed so as to directly wedge apart the adjoining ends of the s ring-ring 26. This constructionis illustrate inFig. 8, in which the abutting ends of the spring-ring 26 have lugs 31, between which is a wedge 27', with a piston 29' thereon, by which it is impelled inward' The wedge 27 carns apart the lugs 31 and expands the sprmg-ring 26 in exactly the same way as the spring-ring 26 was expanded by the three wedges 27.

The operation will be clear from the preceding description. The bull-ring 10 furnishes a bearing or guide for the piston in its movement and is so formed as to constitute a packing-ring as well. The main paeking-rings 19 fit closely upon the cylinder-walls and are uniformly impelled outward thereagainst by the underlying spring-rings 26, together with such additional pressure as is exer-ted by the wedges when the piston is doing heavy dut Under these circumstances the wear iseve y distributed both on the bull-ring and on the main packing-rings. Should the lower section o the bull-ring wear more rapidly than IOO 5 the cylinder-wa s should excessive wearoccur. The main packing-rings 19 may wear to a considerable extent without losing their true cylindrical outline. This is by reason of the fact that they have no appreciablespring tension of their own which Would cause them to Wear unevenly. is furnished' by the interior rings and parts,

which are not exposed to .-wear. The nature of the joint in the main packing-rings 19 is ciable interval, leakage of stearn cannot occur by reason of the 'extension 23, which closes the end of this opening. In like manner this extension is of sufiicient length to close the gap at the end 21'of the web 21. This web is quite thin in practice, so that this gapis' in* considerable in any case.

light; but when the steam-pressure becomes' heavier the temperature in the cylinder becomes also correspondingly raised and the resiliency of the spring-rings is impaired by the. extra temperature; but at this time the extra pressurejexerts a force on the small wedges 27 or 27' as the case may b'e, so that the packing-rings are pressed outward b the wedges with sufficient force, even i the spring-rings artially lose their tension by reason of t e eat. This is a very important feature of the invention and over-comes a defect which has 'been noticed in pistons, particularly those of largecylinders-namely, that they leak steam 'or fluid at the high pressures while perfectly tight when doing light duty. VVhile I have described my invention mainly in connection with pistons of the ordinary form, it is evident that it is applicable for use as a piston-Valve. `When used in this relation, the sectional bull-ring makes an ideal piston-Valve, which fits against its seat in s ite'of continued wear. at I claim is- 1. A piston construction for steam-'enines comprising a main frame or casting aving flat'end faces and having a circumferental groove midway between such faces 5 a bull-ring contained in such groove, sai

of said ward.` All of the spring tension' such as to absolutely prevent leakage of.

It will be seen that'my piston is suitable bull ring being interiorly channeled, a

spring-ring in such channel, packing-r ngs received in said frame or castmg, springrings for-impellin said packing-rings outward, flat metal ks fastened to said flat end faces of the frame or casting, pistons workingin said disks, and wedges on said' pistons and bearing against the spring-rings packing-rings to force the latter out- 2. A piston construction for steam-engines comprising a frame or casting having flat end faces and having a central circumferential groove, a bull-ring in said roove, a spring or normally impelling sai bull-ring outward so as to support the weight thereof, packing-rings received in grooves or channels adjacent the end faces of said frame or casting, metallic disks fastened upon said end faces and ada ted to hold said packingrings in place, a p urality of wedges working inwardly from the end faces of the piston, and small pistons integral with said wedges and open to the steam-pressure at the ends of the` piston for impelling said -packing-rings outward. p

g 3, A piston construction for steam-engines com risin a frame or casting having a central ull-ring, and having reduced portions adjacent the two end faces thereof, metallic disks bolted on said end faces, packing-rin'gs supported by said metallic disks, and istons moving in said metallic disks and aving wedges to impi'nge against said packing- Y -rings to impel the same outward.

4. A piston construction for steam-en es comprising aframe o r casting having a ullring and having reduced portons adj acent to its ends, packing-rings received in said reducedportions, a pair of metallic'disks supported upon the end faces of 'said frame or casting and supporting said packing-rings in IOO place, s ring-rings beneath said packin rin san adaptedtoim elthe same outwar an pistons working t ou h said metallic disks and having wedges a apted to impel said spring-rings outward.'

5. Apiston construction for steam-en ines -comprising a frame or castin having a ull- WALDO M. i CHAPIN', MAY BIRD.

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